I know this might sound odd, but I had unusual results last night.
I was making mini pound cakes by my normal recipe (equal parts by weight egg, flour, sugar and butter) and instead of AP flour, I decided to try Swan Down cake flour.
I cream the butter and sugar, add the eggs and then barely combine the flour and bake.
This last batch came out like a styrofoam cushion! My first thought was I over mixed the batter, but the flour is really just folded in with a spoon.
Is it that I can't do a substitution for cake flour by weight?